After departing USA voluntarilly, will I be allowed to reenter by marrying US citizen?

If charged with overstaying an I-94, the question is how long did you overstay. If less than 180 days (not counting the period of time in voluntary departure status), you would be allowed to reenter through bona fide marriage to a US citizen. If your overstay was 180 days or more but less than a year, you would be barred from reentry for three years. If your overstay was one year or more, you would be barred for 10 years. With marriage to a US citizen, you might be able to qualify for a waiver of the time bar if you fell within the last 2 circumstances so long as you could show that denial of a waiver would cause extreme hardship to your US citizen spouse. You would first have to go through consular processing including being denied at the time of immigrant visa interview before being invited to submit an I-601 waiver application. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.

Depending on the length of your overstay, even voluntary departure will not prevent you from having to apply for a waiver of the unlawful presence bar.  A waiver requires you to prove extreme hardship to a US citizen spouse or child.